This invention relates generally to automatic control devices. More specifically it relates to improvements in pressure responsive electrical switches.
In U.S. Pat. No. 3,875,358 a fluid or gas pressure responsive switch is disclosed effective to control a pump or compressor so as to maintain the pressure in a system between predetermined limits.
It has been found that the performance of a system incorporating the invention of U.S. Pat. No. 3,875,358 and the protection afforded thereby can be improved by the provision of means which prevents operation of the switch when the pressure in the system falls below a predetermined amount.
Therefore, it is an object of this invention to provide a novel pressure responsive electrical switch which automatically operates to interrupt an electrical circuit when the pressure in a closed system falls below a predetermined value.
It is another object of this invention to provide a novel pressure responsive electrical switch which requires manual intervention, insuring that safe conditions are obtained before a switch can resume its automatic control.